Code QA : add declare_strict_types if necessary and remove unused import

[llaville]

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Enhance code

Add new rules to PHP CS Fixer config file to ensure code follows CS defined by the project.

Run PHP CS Fixer on code base (commit 0691215)

php php-cs-fixer.phar fix --dry-run -v --allow-risky=yes

PHP CS Fixer 3.50.0 (8794475) Insomnia by Fabien Potencier, Dariusz Ruminski and contributors.
PHP runtime: 8.2.16
Loaded config default from "/shared/backups/forks/symbol-parser/.php-cs-fixer.dist.php".
Using cache file ".php-cs-fixer.cache".
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   1) src/Parser/PHP/Strategy/UsedExtensionSymbolStrategy.php (declare_strict_types, blank_line_after_opening_tag)
   2) src/Parser/PHP/Strategy/UseStrategy.php (no_unused_imports)
   3) src/Parser/PHP/Strategy/PhpExtensionStrategy.php (declare_strict_types, blank_line_after_opening_tag)

Fixed 3 of 60 files in 0.263 seconds, 18.711 MB memory used